Foot-operated switch



Nov. 21, 1967 w. M. SHOFFNER 3,354,276

FOOT-OPERATED SWITCH Filed June 23, 1966 INVENTOR. WILL/E M. SHOFFNER United States Patent Office 3,354,276 FOOT-OPERATED SWITCH Willie M. Shoifner, 318 S. Lutheran Church Road, RR. 2, New Lebanon, Ohio 45345 Filed June 23, 1966, Ser. No. 559,894 8 Claims. (Cl. 200-865) This invention relates to electric switch and particularly to foot operated electric switches of improved simplified construction.

In many devices the control of the device is obtained by a switch which is often conveniently located for operation by the foot of the machine attendant. Foot operated switches are, of course, well known but heretofore have been relatively complex and expensive and somewhat diificult to obtain in commerce.

The present invention is concerned with a foot operated switch of the nature described which is at once inexpensive, compact, and highly reliable inoperation.

The present invention is furthermore concerned with the provision of an electric switch of the nature referred which can be made either as a simple open and close switch or can be made as a reversing switch.

The present invention also proposes the use of simple inexpensive components to arrive at an inexpensive but highly efiicient switch of the nature referred to.

The exact nature of the present invention and the particular advantages thereof will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective View showing the general appearance of a switch constructed according to the present invention;

FIGURE 2 is a view looking in from the right side of the switch of FIGURE 1 with a cover member removed therefrom and showing the switch constructed as a reversing switch;

FIGURE 3 is a view similar to FIGURE 2 but showing the switch constructed as a simple open and shut switch;

FIGURE 4 is a longitudinal section through the actuating treadle of the switch of FIGURE 2; and

FIGURE 5 is a sectional similar to FIGURE 4 but showing how the treadle of the switch would be constructed for a simple open and closed switch.

Referring to the drawing somewhat more in detail, and with particular reference to FIGURE 1, the switch ac cording to the present invention comprises a base member which carries a treadle 12.

Treadle 12, in the modification of FIGURE 1, is pivoted to the base 12 by a pivot 14 in about the middle of the treadle so the treadle can tilt either way from a neutral position. At one end of base member 10 there is mounted, as by welding, a box 16 which can be a substantially conventional electrical terminal box. The back closed wall of the box is slotted at 18 and extending through slot 18 is the finger 20 of a rod like element 22 fixed to the end of treadle 12 adjacent the box. As will be seen hereafter rod 22 and its finger 20 operate the switch elements contained within box 16.

Turning now to FIGURE 2 it will be seen that inside box 16 is a plate 24. This plate 24 is rotatable on a center defined by a bolt 26. Bolts 26 can, for example, be a shoulder screw and be placed in a bore in the bottom closed wall of box 16 and have plate 24 clamped to the shoulder thereof by nut 23. This will support the plate in the proper position in the box but will permit free rotation thereof within the box. The plate 24 has an aperture 30 therein through which finger 20 of angle rod 22 3,354,276 Patented Nov. 21, 1967 extends. It will be apparent at this point that operation of the treadle 12 will rotate plate 24 in box 16.

Plate 24 carries sets of spring clips 32 and 34 which detachably receive and support respective mercury switch elements 36 and 38. The mercury switch elements are inclined relative to each other and extend in respectively opposite directions so that when plate 24 is in a neutral position both switches are open and when the plate tilts or rotates from its central position in one direction, one of the switches will close and, when the plate is rotated in the other direction from its neutral position, the other of the switches will close and the first switch will open.

The switches can be wired in circuit with a motor M between power lines L1 and L2, as shown, so that the motor can be reversibly controlled or halted merely by tilting the plate 24 to one of its three operative positions.

The entire switch unit is adapted for being secured to a support member 40, which may be a floor or the like, as by screws 42.

As will be seen in FIGURE 4, treadle 12 has position-ed therebeneath a leaf spring member 44 which normally holds the treadle in a neutral position. The spring 44 however permits tilting of the treadle in either direction by the application of pressure to one end or the other of the treadle. It will be seen that the switch is quite inexpensive and utilizes substantially conventional components but it, neve1theless, is easy to operate and is cilicient and highly reliable. No exposed contacts are employed in the switch so that it can be used in location where a switch must be of an explosion free nature.

In the modification of FIGURE 5, the switch construction is the same except that treadle 12a in FIGURE 5 is a single leaf spring element 44a at one end thereof so that the treadle will tilt in only one direction about its support, also form-ed by the spring 44a, upon the application of pressure thereto. The treadle, via the angle rod 22a having the finger 20a thereof extending through the back wall of box 16a, operates plate 24a in rotary movement about its support bolt 26a.

Plate 24a in FIGURE 3 has a single set of spring clips 32:: thereon that support a single mercury tube switch element 36a which is normally open and which, when the plate is rotated, closes.

It will be apparent that both of the switch structures illustrated are quite inexpensive to build and both are usable in locations where switches are required to be explosion proof and that the switches will be highly reliable in operation and convenient to position in the proper location adjacent any piece of equipment which is desired to operate thereby.

In the modification of FIGURES 3 and 5 it has been mentioned that switch element 36a is normally open but it will be understood that this switch element could be normally closed and could open upon tilting of the plate for halting a piece of equipment if so desired.

It will be understood that this invention is susceptible to modification in order to adapt it to diiierent usages and conditions; and accordingly, it is desired to comprehend such modifications within this invention as may fall Within the scope of the appended claims.

What is claimed is:

1. In a switch structure; a horizontal base member, a box fixed to one end of said base member and having a vertical wall extending transversely of the base member, a plate inside the box adjacent said vertical wall, means rotatably supporting the plate on said Wall, switch means on the plate adapted to open and close in response to rotation of the plate in the box, a treadle tiltably supported on said base member and having one end near said wall outside said box, an angle rod fixed to the box end of said treadle and upstanding therefrom and having one end extending through said wall and engaging said plateso that tilting movement of said treadle will cause rotation of said plate in said box, and spring means acting between said base member and said treadle urging said treadle toward one operative position thereof While permitting tilting of the treadle on the base member to cause rotation of said plate to thereby cause actuation of said switch means.

2. A switch structure according to claim 1 in which said switch means comprises mercury tube type switch elements.

3. A switch structure according to claim 2 in which said switch means comprises a single mercury tube type switch element, and said treadle is tiltable in onedirection only from its said one position on said base member.

4. A switch structure according to claim 3 in which said spring member is a leaf spring disposed at the end of said treadle opposite said box and having one end fixed to said treadle and its other end fixed to said base member and serving as the pivotal support for said treadle.

S. A switch structure according to claim 2 in which said switch means comprises two mercury tube type switch elements and said treadl e is pivoted substantially mid-way between its ends to said base member, and said spring means permits tilting of said treadle in both directions from said one position for selectively actuating said switch elements.

6. A switch structure according to claim 2 in which said base member includes means for securing it to a support member. a

7. A switch structure according to claim 2 in which said wall is slotted to receive said one end of said rod and said plate apertured to receive the said one end of said rod.

8. A switch structure according to claim 7 in which said end is adjustably connected to said treadle.

No references cited.

ROBERT S. MACON, Primary Examiner.

H. O. JONES, Assistant Examiner. 

1. IN A SWITCH STRUCTURE; A HORIZONTAL BASE MEMBER, A BOX FIXED TO ONE END OF SAID BASE MEMBER AND HAVING A VERTICAL WALL EXTENDING TRANSVERSELY OF THE BASE MEMBER, A PLATE INSIDE THE BOX ADJACENT SAID VERTICAL WALL, MEANS ROTATABLY SUPPORTING THE PLATE ON SAID WALL, SWITCH MEANS ON THE PLATE ADAPTED TO OPEN AND CLOSED IN RESPONSE TO ROTATION OF THE PLATE IN THE BOX, A TREADLE TILTABLY SUPPORTED ON SAID BASE MEMBER AND HAVING ONE END NEAR SAID WALL OUTSIDE SAID BOX, AN ANGLE ROD FIXED TO THE BOX END OF SAID TREADLE AND UPSTANDING THEREFROM AND HAVING ONE END EXTENDING THROUGH SAID WALL AND ENGAGING SAID PLATE SO THAT TILTING MOVEMENT OF SAID TREADLE WILL CAUSE ROTATION OF SAID PLATE IN SAID BOX, AND SPRING MEANS ACTING BETWEEN SAID BASE MEMBER AND SAID TREADLE URGING SAID TREADLE TOWARD ONE OPERATIVE POSITION THEREOF WHILE PERMITTING TILTING OF THE TREADLE ON THE BASE MEMBER TO CAUSE ROTATION OF SAID PLATE TO THEREBY CAUSE ACTUATION OF SAID SWITCH MEANS. 